Guadalupe Storm-petrel
Encyclopedia
The Guadalupe Storm Petrel (Oceanodroma macrodactyla) is a small seabird
of the storm petrel family
Hydrobatidae. It is apparently extinct.
This species
was almost indistinguishable from its relative, Leach's Storm Petrel. In the field, they could not be told apart except by their circannual rhythm. In the hand, the Guadalupe Storm Petrel could be distinguished by slightly larger size and the paler underwing coverts.
It bred only on Guadalupe Island
off Baja California
(Mexico
), and presumably ranged throughout the region. The breeding season was set between that of the local subspecies of Leach's Storm Petrel, the winter-breeding Oceanodroma leucorhoa cheimomnestes and the summer-breeding O. l. socorroensis, in accordance with Gause's Law.
The single egg, white with a faint ring of reddish-brown and lavender
speckles around the blunt end, was laid in burrows maybe 15 inches (35–40 cm) long, below the Guadalupe Pine (Pinus radiata var. binata)-Island Oak
(Quercus tomentella) cloud forest
on top of Mount Augusta. By mid-June, almost all young had already left the burrows. Though there is little data on Oceanodroma
breeding, incubation
was presumably 42 days or so in this species, just as in similar-sized relatives. Time to fledging must have taken between 60 and 75(-85?) days, most likely around 65 days. This would mean that egg-laying took place from early February to March, and that in April–May, unfledged young were present in most active burrows. just as in their relatives, the egg was incubated a few days by either parent, after which the other took over, the relieved bird taking to the sea to satiate themselves for the next incubation stint. The young were fed only at night, also like in other storm-petrels.
Three species of lice were found to parasitize the Guadalupe Storm Petrel: the menoponids
Longimenopon dominicanum and Austromenopon oceanodromae, and the ischnocera
n Halipeurus raphanus. The second also occurs on some other storm petrels, and the third was also found on the Ashy Storm Petrel. L. dominicanum on the other hand has to date not been found on other birds and seems to be a case of coextinction
.
s to the island decimated the population during the late 19th century. By the end of the 1906 breeding season, it was still considered "abundant" though of course the "large numbers" of birds present there and then must have been nearly the entire population of this species. Still, it was noted that
The last two specimens were supposedly collected between May 2 and May 5, 1911 and the last record of a breeding bird was in 1912. The species has not been seen since. Only old, abandoned burrows and the decayed remains of storm petrels killed by cats were found in the years thereafter. However, the Guadalupe Storm Petrel cannot be distinguished from the sympatric O. leucorhoa in the field, and surveys on Guadalupe invariably took place outside the breeding season of O. macrodactyla, focussing on researching the local Leach's Storm Petrels. Thus, there remained some hope for the present species' survival, or rather, its extinction could not be definitely confirmed.
From June 4 to June 10, 2000, the Guadalupe Storm Petrel's breeding grounds were finally surveyed at the correct time. Had the species survived, not only would recently fledged immature birds have been present, but also all signs of a recently ended breeding season, such as eggshells and freshly used burrows retaining the musky smell of these birds. In the words of the expedition's primary researcher, Exequiel Ezcurra of the San Diego Natural History Museum
,
The official classification by the IUCN has not been updated yet. In any case, the precautionary principle
would probably require a few years of follow-up surveys, possible now that restoration of Guadalupe's ecosystem is underway.
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
of the storm petrel family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Hydrobatidae. It is apparently extinct.
Description and ecology
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
was almost indistinguishable from its relative, Leach's Storm Petrel. In the field, they could not be told apart except by their circannual rhythm. In the hand, the Guadalupe Storm Petrel could be distinguished by slightly larger size and the paler underwing coverts.
It bred only on Guadalupe Island
Guadalupe Island
Guadalupe Island, or Isla Guadalupe is a volcanic island located 241 kilometers off the west coast of Mexico's Baja California peninsula and some 400 kilometers southwest of the city of Ensenada in Baja California state, in the Pacific Ocean...
off Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
(Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
), and presumably ranged throughout the region. The breeding season was set between that of the local subspecies of Leach's Storm Petrel, the winter-breeding Oceanodroma leucorhoa cheimomnestes and the summer-breeding O. l. socorroensis, in accordance with Gause's Law.
The single egg, white with a faint ring of reddish-brown and lavender
Lavender (color)
Lavender is a pale tint of violet. It applies particularly to the color of the flower of the same name. The web color called lavender is displayed at right—it matches the color of the very palest part of the lavender flower; however, the more saturated color shown below as floral lavender more...
speckles around the blunt end, was laid in burrows maybe 15 inches (35–40 cm) long, below the Guadalupe Pine (Pinus radiata var. binata)-Island Oak
Island Oak
Quercus tomentella, the Island Oak, also the Island Live Oak or Channel Islands Oak, is an oak in the section Protobalanus.-Distribution:...
(Quercus tomentella) cloud forest
Cloud forest
A cloud forest, also called a fog forest, is a generally tropical or subtropical evergreen montane moist forest characterized by a persistent, frequent or seasonal low-level cloud cover, usually at the canopy level. Cloud forests often exhibit an abundance of mosses covering the ground and...
on top of Mount Augusta. By mid-June, almost all young had already left the burrows. Though there is little data on Oceanodroma
Oceanodroma
Oceanodroma is a genus of storm petrels. The genus currently comprises 15 species. One species, the Guadalupe Storm Petrel , is extinct....
breeding, incubation
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
was presumably 42 days or so in this species, just as in similar-sized relatives. Time to fledging must have taken between 60 and 75(-85?) days, most likely around 65 days. This would mean that egg-laying took place from early February to March, and that in April–May, unfledged young were present in most active burrows. just as in their relatives, the egg was incubated a few days by either parent, after which the other took over, the relieved bird taking to the sea to satiate themselves for the next incubation stint. The young were fed only at night, also like in other storm-petrels.
Three species of lice were found to parasitize the Guadalupe Storm Petrel: the menoponids
Menoponidae
Sometimes referred to as the chicken body louse family, the Menoponidae are a family of a larger group Amblycera of the chewing lice. Most commonly they are ectoparasites of a wide range of birds....
Longimenopon dominicanum and Austromenopon oceanodromae, and the ischnocera
Ischnocera
The Ischnocera is a large suborder of lice mostly parasitic on birds but including a large family parasitic on mammals. The genus Trichophilopterus is also found on mammals but probably belongs to the "avian Ischnocera" and represents a host switch from birds to mammals...
n Halipeurus raphanus. The second also occurs on some other storm petrels, and the third was also found on the Ashy Storm Petrel. L. dominicanum on the other hand has to date not been found on other birds and seems to be a case of coextinction
Coextinction
Coextinction of a species is the loss of a species as a consequence of the extinction of another. The term was originally used in the context of the extinction of parasitic insects following the loss of their specific hosts...
.
Disappearance
The introduction of catCat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
s to the island decimated the population during the late 19th century. By the end of the 1906 breeding season, it was still considered "abundant" though of course the "large numbers" of birds present there and then must have been nearly the entire population of this species. Still, it was noted that
"[t]he mortality among these birds from the depredations of the cats that overrun the island is appalling - wings and feathers lie scattered in every direction around the burrows along the top of the pine ridge."
The last two specimens were supposedly collected between May 2 and May 5, 1911 and the last record of a breeding bird was in 1912. The species has not been seen since. Only old, abandoned burrows and the decayed remains of storm petrels killed by cats were found in the years thereafter. However, the Guadalupe Storm Petrel cannot be distinguished from the sympatric O. leucorhoa in the field, and surveys on Guadalupe invariably took place outside the breeding season of O. macrodactyla, focussing on researching the local Leach's Storm Petrels. Thus, there remained some hope for the present species' survival, or rather, its extinction could not be definitely confirmed.
From June 4 to June 10, 2000, the Guadalupe Storm Petrel's breeding grounds were finally surveyed at the correct time. Had the species survived, not only would recently fledged immature birds have been present, but also all signs of a recently ended breeding season, such as eggshells and freshly used burrows retaining the musky smell of these birds. In the words of the expedition's primary researcher, Exequiel Ezcurra of the San Diego Natural History Museum
San Diego Natural History Museum
The San Diego Natural History Museum was founded in 1874 as the San Diego Society of Natural History. The present location of the museum in San Diego's Balboa Park was dedicated on January 14, 1933....
,
"We searched thoroughly for the Guadalupe Storm Petrel, and failed to find it. Sadly, we are now more ready to admit that the species is indeed extinct. Never, since the 1920s, had so much search effort been devoted to this species. At different times, more than 10 researchers looked for the elusive creature. It simply was not there."http://www.sdnhm.org/research/guadalupe/updates.html
The official classification by the IUCN has not been updated yet. In any case, the precautionary principle
Precautionary principle
The precautionary principle or precautionary approach states that if an action or policy has a suspected risk of causing harm to the public or to the environment, in the absence of scientific consensus that the action or policy is harmful, the burden of proof that it is not harmful falls on those...
would probably require a few years of follow-up surveys, possible now that restoration of Guadalupe's ecosystem is underway.